NASA's Space Shuttle, officially calle Space Transportation System (STS), is the United States government's current manned launch vehicle. The winged Space Shuttle orbiter is launched vertically, usually carrying five to seven astronauts (although eight have been carried) and up to 50,000 lb (22 700 kg) of payload into low earth orbit. When its mission is complete, the Shuttle can independently move itself out of orbit (by means of its maneuvering thrusters) and re-enter the Earth's atmosphere. During descent and landing, the Shuttle Orbiter acts as a glider and makes a completely unpowered landing.